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[英]I can't put a ArrayList with a bundle from a fragment into another fragment
[英]How can I pass values from 1 fragment to another with Bundle()?
我发现这段代码可以将数据从一个片段传递到另一个片段:
片段 1:
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
Fragment2 fragment2 = new Fragment2();
Bundle bundle = new Bundle();
bundle.putString("data", data);
fragmentTransaction.replace(R.id.fragment_container, fragment2);
fragmentTransaction.addToBackStack(null);
fragmentTransaction.commit();
片段 2:
Bundle bundle = getArguments();
assert bundle != null;
String data = bundle.getString("data");
但我不想改变片段。 所以我删除了它的一部分。 但它不起作用。 这是我的代码:
片段 1:
public void openActifity2(){
Fragment_score fragment_score = new Fragment_score();
Bundle bundle = new Bundle();
bundle.putInt("FINISHED_LEVELS", finishedLevels);
bundle.putInt("FAILED_LEVELS", failedLevels);
bundle.putInt("SKIPPED_LEVELS", skippedLevels);
bundle.putInt("USED_HINTS", usedHints);
fragment_score.setArguments(bundle);
}
片段 2:
Bundle bundle = getArguments();
int finishedLevels = bundle.getInt("FINISHED_LEVELS");
int failedLevels = bundle.getInt("FINISHED_LEVELS");
int skippedLevels = bundle.getInt("FINISHED_LEVELS");
int usedHints = bundle.getInt("FINISHED_LEVELS");
我必须使用我在互联网上找到的代码还是我的版本也可以工作? 打开第二个片段时出现此错误:
E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.rexan_snerficonquiz, PID: 20931 java.lang.NullPointerException: Attempt to invoke virtual method 'int android.os.Bundle.getInt(java.lang.String)' on a null object reference at com.example.rexan_snerficonquiz.Fragment_score.onCreateView(Fragment_score.java:26) at androidx.fragment.app.Fragment.performCreateView(Fragment.java:2600) at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManagerImpl.java :881) at androidx.fragment.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManagerImpl.java:1238) at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManagerImpl.java:1303) a t androidx.fragment.app.BackStackRecord.executeOps(BackStackRecord.java:439) at androidx.fragment.app.FragmentManagerImpl.executeOps(FragmentManagerImpl.java:2079) at androidx.fragment.app.FragmentManagerImpl.executeOpsTogether(FragmentManagerImpl.java:1869 ) at androidx.fragment.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManagerImpl.java:1824) at androidx.fragment.app.FragmentManagerImpl.execPendingActions(FragmentManagerImpl.java:1727) at androidx.fragment.app.FragmentManagerImpl$2.run(FragmentManagerImpl.java :150) at android.os.Handler.handleCallback(Handler.java:938) at android.os.Handler.dispatchMessage(Handler.java:99) at android.os.Looper.l oop(Looper.java:223) at android.app.ActivityThread.main(ActivityThread.java:7523) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller. run(RuntimeInit.java:592) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:941)
为了避免出现错误,试试这个
Bundle bundle = getArguments();
if(bundle != null){
int finishedLevels = bundle.getInt("FINISHED_LEVELS", "DEFAULT_VALUE");
int failedLevels = bundle.getInt("FINISHED_LEVELS", "DEFAULT_VALUE");
int skippedLevels = bundle.getInt("FINISHED_LEVELS", "DEFAULT_VALUE");
int usedHints = bundle.getInt("FINISHED_LEVELS", "DEFAULT_VALUE");
}
根据您的评论,您可以在onOptionsItemSelected
方法中更改片段
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.action_1) {
// add your action here that you want
return true;
}else if (id==R.id.action_2) {
// add your action here that you want
return true;
}
return super.onOptionsItemSelected(item);
}
如果您更改片段,那么您的代码将可以正常工作。 但是如果你不想改变片段而不是 1) int finishedLevels = bundle.getInt("FINISHED_LEVELS", 0);
或 2) 代替捆绑使用 static 全局变量public static int finishedLevels = 0;
在片段 1中,然后使用 class 名称引用简单地在片段 2中获取它们的值。 注意:如果您不想更改片段并想要片段 2中的值,那么我会推荐static 变量
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